Long-term evaluation of the influence of smear layer removal on the sealing ability of different sealers

The purpose of this study was to examine the effect of the smear layer on apical microleakage over 16 wk. One hundred and four extracted human teeth were assigned to four groups treated as follows: group A1 - smear layer was left intact and canals were obturated with gutta-percha and Roth 811; group A2 - smear layer was left intact and canals were obturated with gutta-percha and AH26; group B1 - smear layer was removed and canals were obturated with gutta-percha and Roth 811; and group B2 - smear layer was removed and canals were obturated with gutta-percha and AH26. Microleakage was measured by the electrochemical method. In parallel, 12 teeth were examined under a scanning electron microscope, The results indicated that the smear layer removal resulted in a statistically significant reduction of microleakage values in groups obturated with AH26. The presence or absence of smear layer had no significant effect on the sealing ability of Roth 811.